Air conditioning system



L.. A. PHILIPP A1B CONDITIONING SYSTEM Filed Nov. 8, 1935 INVENTOR.

direz/yc: f2., PML/PP ATTORNEY.

lll

atented Nov. 19, 1940 TENT OFFICE.

AIR CONDITIONING SYSTEM Lawrence A. Philipp, Detroit, Mich., assigner, by mesne assignments, to Nash-Kelvinator Corporation, Maryland Detroit, Mich.,

a corporation of Application November 8, 1933, Serial No4. 697,169

16 Claims.

Aluurnidiiying air.

One of the objects of the present invention is to provide an improved method of and apparatus for conditioning air, utilizing a heat absorber aboutV which air to be conditioned is circulated and varying the quantity of heat removed from. the circulating air by different portions of the heat absorber in accordance with the relative-humldity of the air to be conditioned; to cause one portion oi the heat absorber to increase and another portion thereof to decrease in temperature in accordance with the relative humidity of the air to be conditioned; to control the temperature oi the heat absorber in accordance with the ternperature of the air to be conditioned and controlling the amount of heat absorbed by dierent portions of the heat absorber in accordance with the changes in the relative humidity oithe air to be conditionedp O Other and further objects and advantages will be apparent from the following disclosure, rei'- erence being had to the accompanying drawing wherein a preferred form of embodiment of the present invention is clearly shown.

ln the drawing;

Fig. 1 illustrates diagrammatically my improved airrconditioning system as applied for cooling a room; Fig. 2 is a cross sectional view of an expansion valve, and Fig. 3 is a cross sectional View of another control valve used in the system. -ll/ly invention contemplates the use of a heat absorber of any suitable type about which a part oi the air to be conditioned is circulated yover one portion of the-heat absorber for the purpose of removing principally sensible heat from the air. Part of the air to be conditioned is circulated over another portion of the heat absorber, which latter portion is utilized, particularly when the air to, be conditioned is high in relative'humidity, for cooling the air to below its dew point in order to cause preclpitationand thereby removal of a large part of the moisture from the air.

In the present embodiment an evaporator III oi a mechanical refrigerator is employed as a heat absorber and the two heat absorbing surfaces of the heat absorber are provided by dividing the evaporator into two sections or portions L heat dissipator is herein shown as comprising a. reciprocating type compressor I t, a condenser ligand a receiver for liquid refrigerant 2t. Gaseous refrigerant withdrawn from the sections II and I2 passes through the suction pipe Il into the low pressure side of the compressor It wherein' it is compressed and flows into the condenser where it is liquefied by being cooled and from the condenser the liqueh'ed refrigerant flows into the receiver c2li and then conducted to the expansion valves I5 and It through liquid refrigerant feed pipe Iii. The compressor is driven bya motor 22 which is controlled by 'a switch 23. It is to be understood that the capacity oi the machine is such as to provide suiiicient refrigeration under abnormal lhigh temperature and humidity conditions or both oi the air to be conditioned ande that the reirigerating effect is varied in accordance with the conditions of the air to be conditioned.

The air conditioner herein illustrated is the type for cooling a room 2l such as an cnice or a living room in the home and the evaporator Ill is disposed in a cabinet 25 having an air inlet 26 and an air outlet 2l. The air is iorcedthrough the cabinet and about the evaporator It by a fan 23 driven by an electric motor 2t. A. partition (tu extends downwardly from the top of the cabinet 2F and from the front to the back for directing air. The sections II and I2 of the evaporator are arranged side Aby side and ap- Cproxirnately one-half of the air circulated'passes about section II and the other half about sec tion I2. Section I2 has approximately as much u heat absorbing surface as section II. In order to increase the heat absorbing surfaces of sections I I and I2, iins 3| and 32 are attached to these sections. Water collected on Athe evaporators drips to the floor of the cabinet 25 and is conducted out of the cabinet through a drain pipe 33. outside of the room to be conditioned but in case it is desirable to havethis machine in the room, the condenser and compressor are cooled by water so that'v4 the heat is carried out of the room in the water. f 1

The primary or principal purpose of section II is to remove sensible heat ifrom all of the air passing thereover and although section I2 will remove sensible heat from the air passing thereover, its function at times, particularly when the relative humidity of the air to be conditioned is high, is to remove latent heat from the air by lowering the temperature of such air to considerably below its dew point. It will be appre- Preferably the heat dissipator is disposed ciated that the air in the room is subjected to different conditions due to changes in the temperature and humidity of the air outside the room and due to the direct addition of heat and 5 moisture to the air Within the room.

In order to maintain the air in the room between predetermined high and low temperature limits, a thermostat 34 is provided for controlling the operation of the heat dissipator. This thermostat is preferably disposed so as to respond to the mean temperature of the air in the room and controls the motor switch 23 by opening the same when the temperature of the air in the room attains a predetermined low value and closes the same when the temperature of theL air attains a predetermined high value. Thus the temperature of the air in the room is maintained between certain limits by controlling the operation of the heat dissipator.

Not only is it desirable to control the temperature of the air in the room but, it is also desirable to control the relative humidity of the air. This is accomplished by lowering the temperature of part of the air, as it passes through the cabinet 25, to below its dew point to cause precipitation or increased precipitation of the moisture out of the air. The section I2 of the evaporator I0 is used for this purpose, it being designed and controlled to main at times a ternperature much lower than that of the section II. Since the relative humidity varies independently of variations in temperature, it is necessary to remove varying proportions of moisture from the air while maintaining the temperature of the air between the predetermined xed high and low temperature limits. In other words it is necessary at times to provide a low temperature to remove sufcient moisture and it is also necessary that the temperature should not be lowered be- 40 low a predetermined limit. Toprovide these proper refrigerating conditions, I vary the amount of heat absorbed by different portions of the evaporator I9 by increasing the temperature of one portion and decreasing the tempera- 45 ture of another portion of the evaporator. These portions in the present disclosure are sections I I and I2. When the relative humidity of the air to be conditioned is relatively high, the section I2 is arranged to operate at a low tempera- 50 ture and the section II is either ineffective or operates at a relatively high temperature. The temperature of the section I2 at this time will be low enough `to cool a portion of the air to considerably below its dew point and the amount 55 of heat units removed by the evaporator is sufcient only to maintain the temperature of the air in the room between its predetermined xed high and low temperature limits.

'Ihe differential in temperature between the 60 sections Il and I2 or the relative amounts of heat absorbed by said sections car be controlled by preventing circulation or restricting the circulation through one of the sections. For this purpose, I provide a valve 35 which is controlled 65 lby a humidostat 36. Valve 35 comprises a casing 38 which is fluid tight and incloses a solenoid including a core 39 and a magnet coil 40. Core 39 is arranged to open and close a port 4I to control the flow of gaseous refrigerant from 70 evaporator section II. If desirable, a by-pass 42 for the port 4I may be provided which by-pass permits a restricted flow of refrigerant from the section II to the interior of the casing 38 when the core is on its seat. When the magnet 75 coil 40 is de-energized, the core rests upon its seat and, if the by-pass is provided, the refrigerant can flow from the section II only through by-pass 42, however, when the magnet coil is energized, the core is lifted from its seat permitting an unrestricted flow of refrigerant from section II to the interior of the casing. The magnet coil 40 is controlled by the humidostat 36. When the percentage 0f relative humidity is proper, the humidostat causes current to ow through coil 4U so that the flow of refrigerant from section II to compressor I8 is unrestricted but when the percentage of relative humidity is too high, the circuit to the coil 40 is interrupted by the humidostat whereby refrigerant ow from section II to the compressor I8 is interrupted, or, if by-pass 42 is provided, the flow from section II is restricted to that which can pass through by-pass 42.

The expansion valves I5 and I6 are identical in construction and valve I5 is shown in detail in Fig. 2. Each valve comprisesa casing 45 and a casing 46 with a diaphragm 4'I sealed therebetween to form chambers 49 and 59. A spring 52 is disposed within chamber 49 and is adjustably set by a screw 53. The threaded opening for this screw is closed 'by a cap 54. A tube 5B connects the interior of chamber 49 with a thermostat 5'I which thermostat is in intimate metallic contact with the outlet of evaporator section I I and contains a volatile fluid. A valve 59 is attached to the diaphragm 4'I and the stem thereof extends through a port SI) in a wall of casing 46. This valve 59 controls the flow of refrigerant from the liquid pipe I3 to the chamber 50 and the inlet 0f evaporator section II is fed from this chamber.

The movement of diaphragm 41 and likewise the opening and closing of valve 59 of expansion valve I5 is governed by the differenti/a1 in pressures on opposite sides of the diaphragm. The pressure of the volatile fluid in chamber 49 is governed by the temperature at the outlet of the evaporator section II. When the temperature at the outlet of section II is high, the pressure in chamber 49 is high, and vice versa. 'Ihe pressure in chamber 50 is governed by the pressure of the refrigerant in section II. When the pressure of the refrigerant in section II is high, the pressure in chamber 50 is high, and vice versa.

When the effect of the pressure on the chamber 50 side of diaphragm 4'I overbalances that of the opposite side of the diaphragm, valve 59 will be closed but when gaseous refrigerant is withdrawn from section II to reduce the pressure in section II, the valve will open. Now when only a limited amount of refrigerant is withdrawn from the section II only a corresponding amount of refrigerant, will be admitted to the section II through valve 59 and therefore the temperature of the section willbe relatively high. However, if the flow 0f refrigerant is not so restricted, the pressure within the section II will be lowered permitting'aJ larger quantity 0f refrigerant to enter thesection through valve 59 and consequently, the section will operate at a relatively lower temperature. The lower temperature operation of the section II is also governedby the thermostat 51 in such manner that after the temperature at the outlet of the section is lowered to a predetermined minimum, the pressure of the volatile fluid in chamber 49 is reduced to such value whereby the pressure in chamber 59 overbalances that ,in chamber 49 and causes the diaphragm to close valve 59 or to so retard the -flow of liquid refrigerant therethrough as to maintain the temperature ofthe evaporator section at its predetermined low value. The thermostat 51 is preferably placed n in intimate metallic Contact with the outlet of the evapor'ator and when refrigerant vaporizes at this point, at which time the evaporator section is operating at full capacity, this vaporisation causes a material lowering of the temperilu ature at the outlet of the evaporator and of the volatile fluid in thermostat 51 and a consequentv material lowering of the pressure vin the thermostat and in chamber 49 to aect the movement of the lvalve 59 as above described.

lit Expansion valve I6, which controls the fiow ofv ter the section and it will operate at a warmer' temperature.

lff the flow of gaseous refrigerant from the tu section il is restricted as by the solenoid valve dit, the pressure within the section II will be higher than when there is no restriction to the withdrawal of gaseous refrigerant as when the solenoid valve 39 is open. Therefore section II du will operate at a warmer temperature when valve 39 is closed than when said valve is open. lit will be observed that at this time, the suction of the compressor is substantially concentrated on reducing the pressure in section I2 since du gaseous refrigerant can freely flow therefrom and only a limited amount of gaseous refrigerant escapes through the valve 35 and therefore the temperature of section I2 is reduced to a relatively low temperature. The adjustment or in setting of the expansion valves I5 are such that when solenoid valve 39 is closed, the temperature of section I2 is low enough s0 that such air passing thereover, is cooled to considerably below its dew point whereby to remove the necesuu sary moisture so that the air is maintained at the proper relative humidity. The combined cooling effect of sections II and I2, governed by the length of operation of thecompressor I8 as controlled by thermostat 34, will adequately cool du the air to the desired temperature and the section I2 will cool the air suiciently to remove the required amount of moisture for proper humidity conditions.

If the relative humidity is low, the humidostat du will cause current to ow through magnet coil t9 to open the port 4I. Gas can then readily now from the section II to the compressor and the suction of the compressor will no longer be concentrated primarily on the section I2. By 165i increasing the ow of gaseous refrigerant from section II-, its temperature will be reduced to a lower value. Since the suction action of the compressor is no longer concentrated primarily'on section I2, the pressure in both sections II and I2 im will be substantially the same, section I I decreas- ,ing in temperature and section I2 increasing in temperature and both sections will then operate at a temperature to remove principally sensible heat from the air. it Qurrent for the motor 22 is conducted through wires 92 and ft, the current passing through contact tt and movable contact t5 of the snap acting switch 29. The contact t5 of this switch is actuated by a fluid tight bellows t6 which is connected with the volatile fluid containing 6 thermostat itil. by a pipe tl. The humidostat 36 is connected in parallel with the compressor motor ff by wires t9 and 'ill and fan motor 29 by wires lll and lf.

From the foregoing, it will be apparent that 10 I have provided an airconditioning system in which the temperature of the air will be maintained between predetermined high and low temperature limits. The room thermostat 34 controls the starting and stopping of the compressor it to provide the proper temperatureof the air and this is accomplished regardless whether the evaporator sections are functioning to remove both latent and sensible heat or functioning to remove primarily sensible heat. Byy providing for varying the temperature differential between sections ll and it so that one section is reduced to a temperature low enough to remove latent heat while the other section is increased in temperature, I have provided a system in which even temperature and desired humidity for a room is insured.

It will be observed that the cabinet is so constructed that the air which is not cooled or cooled slightly only, as the case may be, by section ill, commingles, in the lower part of the cabinet and while passing upwardly, with the relatively cold air which passed about section y l2.

Under certain conditions, it will be desirable to causel some precipitation of moisture at the sections l-i yand if when the valve 39 is open, and it is to be understood that when said section or portion in is referred to as functioning `to remove principally sensible heat, such terms are used merely to define the main functional 40 purpose of the section as distinguished from the main functional purpose of section or portion I2 at the time valve 39 is closed.

While the form of embodiment of the present invention as herein disclosed constitutesa preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows: A

1. The process of conditioning air which`comprises causing the air which is to be conditioned to circulate in heat exchange relation with a cooling surface and causing a portion only of the cooling surface to decrease to a lower temperature than another portion of said cooling surface in accordance with an increase of relative humidity of the air to be conditioned and causing said first portion only to increase in temperature in accordance with a decrease of relative humidity of the air to be conditioned.

2. The process of conditioning air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a cooling surface and causing a portion of the cooling surface to increase in temperature and another portion of the cooling surface to decrease in temperature in accordance with the relative humidity of the air to be conditioned.

, 3. The process of cooling and dehumidifying ir which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a surface cooled by a refrigerating medium, controlling the heat exchange between the medium and said surface in accordance with the temperature of the air to be conditioned,

ance with an increase of relative humidity of the air to be conditioned and causing said first portion only to increase in temperature in accordance with a decrease of relative humidity of the air to be conditioned.

4. An air conditioning system comprising in combination, means providing a cooling surface for cooling circulating air, control means for causing a portion of the cooling surface to increase in temperature and for causing another portion of the cooling surface to decrease in temperature, and means responsive to the relative humidity of the air to be conditioned for actuating said control means.

5. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a portion of an evaporator of a mechanical refrigerator, the principal function of which portion is to remove sensible heat from the air, and in heat exchange relation with another portion of the evaporator, the function of which latter portion is to cool the air to below the dew point thereof, controlling the flow of refrige-rating medium through the first mentioned portion of the evaporator in accordance with the changes in temperature of the air to be conditioned, and controlling the flow of refrigerating medium through the second mentioned portion of the evaporator in accordance with the changes in the relative humidity 'of the air to be conditioned.

6. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a portion of an evaporator of a mechanical refrigerator, the main function of which portion is to remove principally sensible heat from the air, and in heat exchange relation with another portion of the evaporator, the function of which latter portion is to cool the air to below the dew point thereof, controlling the amount of heat absorbed by the first mentioned and second mentioned portions of the evaporator in accordance with the changes in temperature and changes in the relative humidity, respectively, of the air to be conditioned.

7. The process of controlling the temperature and the humidity of air which comprises causing air, which is to be conditioned, to circulate in heat exchange relation with a heat interchanger and causing agportion of the heat interchanger to decrease in temperature and another portion to increase in temperature simultaneously in accordance with the condition of the air to be conditioned. ,x

8. An air conditioning system comprising in combination, means providing a coolinglsurface over which air to be conditioned is circulated, and means responsive to an increase of relative humidity of the air to be conditioned for causing a portion only of said surface to decrease to a lower temperature than another portion of the cooling surface and responsive to a decrease of relative humidity of the air for causing saidfrstk the air.

ture differential between different portions of said surface during such changes in relative humidity.

10. The method of controlling the humidity and temperature conditions of air by a mechanical refrigerating system employing evaporating means comprising a plurality of evaporators connected with a compressor and condenser and in which the evaporators are connected in parallel circuit relation, which method comprises causing air to circulate over the evaporators; and while the compressor is in operation, varying the refrigerating effect of the evaporating means by controlling the flow of refrigerant from one of the evaporators in accordance with changes in one of the said conditions of air.

l1. The method of controlling the humidity and temperature conditions` of air by a mechanical refrigerating system employing evaporating means comprising a plurality of evaporators connected with a compressor and condenser and in which the evaporators are connected in parallel circuit relation, which Imethod comprises causing air to circulate over the evaporators; and while the compressor is in operation, varying the refrigerating effect of the evaporating means by controlling the flow of refrigerant to one of the evaporators in accordance With changes in one of the said conditions of the air.

12. The method of controlling the humidity and temperature conditions of air by a mechanical refrigerating system employing evaporating means comprising a plurality of evaporators connected with a compressor and condenser and in which the evaporators are connected in parallel circuit relation, which method comprises causing air to circulate over the evaporators; causing the compressor to operate in response to one of the said conditions of the air; and While the compressor is in operation, varying the refrigerating effect of the evaporating means by controlling the flow of refrigerant to one of the evaporators in accordance with changes in the other condition of the air.

13. The process of controlling the humidity and temperature conditions of air by a mechanical refrigerating system employing an evaporator connected with a compressor and a condenser, which process comprises causing air to circulate over the evaporator; and while the compressor is in operation, varying the refrigerating effect of the evaporator by decreasing and increasing the flow of refrigerant to the evaporator in accordance with changes in oneA of the said conditions of the air.

14. The process of lcontrolling the humidity and temperature conditions of air by a mechanical refrigerating system employing an evaporator connected with a compressor and a condenser, which process comprises causing air to circulate over the evaporator; causing the compressor to operate in response to one of the said conditions of the air; and while the compressor is in operation, varying the effect of the evaporator by increasing and decreasing the ow of refrigerant tor the evaporator in accordance with changes in the other said condition of 15. The method of controlling the humidity and temperature conditions of air by a mechanical refrigerating system employing evaporating means comprising a plurality of evaporators connected with a compressor and condenser and in which the evaporators are connected in paralici circuit relation, which method.D comprises Vcausing air to circulate over the evaporators; and

While the compressor is in operation, varying the refrigerating eiiect of the evaporating means 'by controlling the ow of refrigerant through denser, which process comprises causing air to `circulate over the evaporator, causing'the compressor to operate in response to changes in the' temperature condition of the air, and while the compressor is in operation, varying the effect of the evaporator by increasing and decreasing the ow of refrigerant through the 'evaporator' in accordance with changes in the relative humidity of the air.

LAWRENCE A. PHILIPP. l0 

